Abstract
Suspension is an component of the important assembly of the automobile, it guarantees to contact with a flexible between the wheels or axles and bearing system (or load-frame body), and can transfer loads、relax impulsion、reduce vibration and regulate the body position of the vehicle in traffic, and have a direct impact on ride comfort and operate stability.
At present, vehicles generally used the passive suspension, which is consisted of the flexibility components and the shock absorber. Due to the suspension system’ parameter was fixed, it chooses compromise for the conflicting design requirements, such as the operate stability and ride comfort and so on, but as to the automobile in volatile work environment, the passive suspension is difficult to satisfy anticipant performance requirements. According to the road situation, the active suspension can adjust to and produce the necessary suspension control between the wheels and the body in a timely, which contain the body’s vibration, so that the suspension keep in the optimal damping state, at the same time, and achieve the purpose on improve the ride comfort and operate stability of the vehicle . It can be said that, this is an important direction of the development research of the automobile suspension in future. Therefore, aim at this problem, the paper put up for modeling, simulation study.
Firstly, according to the Newton theorem, the paper use the vehicle dynamics theory, and set up the dynamics model of the passive suspension and the second freedom active suspension system based on a quarter of the body. Taking into account an important impact of the road surface disturbance to enter for the suspension control, and enter the road input and the initiative to control signals with input, as to further simplify the form of the differential equations. And translate the differential equations into a form of expression of the state equations. And establish the road roughness mathematical model of the road input signal for sine, step random and white noise signal, and achieve the simulation. At the same time, outlined the three eva luation index of the suspension performance, such as the body vertical acceleration, the relatively dynamic load of the wheel, the suspension dynamic deflection. And build the simulation model plans of the control system of the automobile suspension by the Matlab7.0/Simulink software, including the importable model of the road, the passive suspension model, the active suspension model of the PID control. And run the simulation model map to achieve the simulation of the different input signal of the suspension control system. Finally, according to several different road of the incentive signal under the different control means, and analysis the simulation results of the eva luation index of the suspension performance in-depth.
This paper can provide theoretical foundation and numerical reference for the experimental research and product development of the active suspension.
Keywords: Vehicle engineering Active suspension MATLAB Modeling
PID control Simulation
目 录
目录 1
中文摘要 3
Abstract 4
第一章 绪论 5
1.1 研究背景 6
1.2 研究的目的与意义 7
1.3 研究的主要內容及方法 7
第二章 悬架的概述及类型 9
2.1 悬架的概述 9
2.2 悬架的类型 9
2.2.1 被动悬架 10
2.2.2 半主动悬架 11
2.2.3 主动悬架 12
2.2.4 各种悬架性能比较 14
第三章 悬架的系统建模与性能评价 15
3.1 引言 15
3.2 汽车主动悬架的工作原理 15
3.3 汽车主动悬架的动力学模型 16
3.3.1 常用的基本车体模型的简化及假定条件 17
3.3.2 基于四分之一车体的被动悬架动力学模型的建立 18
3.3.2 基于四分之一车体的主动悬架动力学模型的建立 19
3.4 随机路面模型 20
3.4.1 路面不平度的功率谱密度 20
3.4.2 空间谱密度与时间谱密度的转化 21
3.5 悬架的性能评价标准 24
第四章 主动悬架PID控制理论的研究 25
4.1 PID控制的简介 25
4.2 PID控制原理 26
4.3 主动悬架系统的PID控制 27
4.4 PID控制的参数整定 29
第五章 悬架的建模及仿真 30
5.1 仿真环境介绍 30
5.1.1 MATLAB的简介 30
5.1.2 SIMULINK的技术简介 31
5.2 主动悬架仿真控制模型的建立 32
第六章 悬架的仿真过程及分析 41
6.1 车辆悬架仿真过程 42
6.2 车辆悬架仿真结果分析 42
6.2.1 不同控制方法下的簧载质量加速度的比较 43
6.2.2 不同控制方法下的悬架动挠度的比较 46
6.2.3 不同控制方法下的悬架动载荷的比较 49
6.3 本章小结 53
第七章 结论 54
参考文献 56
致谢 57
